IDC, interleaved alt PH/HT (no FR)

IDC H ttt P ttt H
IDC P ttt H ttt P

t 57.6
D 6527.4
TP 1620
TPS 28.1
DPT 4.0
DPS 113.3

So this is the highest dps rotation possible? How come you don't get more damage from using HT first, or getting PH up faster?